Tunnel liner



July 24. 1934.

TUNNEL LINER Filed Deo. 11, 1931 2 sheets-sheet, 1

E. WHITE- 1,967,489

11, 1931 2 sheets-sheet. 2

H. E. WHITE July 24, 1934.

TUNNEL LINER Filed Deo..

JWN

Patented July 24, 1934 4UNITED 'STATES PATENT OFFICE TUNNEL LINER Application December 11, 1931, Serial No. 580,480

3 Claims.

In the construction'of tunnel liners, and particularly those made of plate metal that are deformed to produce curved sections or members, it has been the custom to provide reenforcing usually have been in the form of corrugations which lare inset with respect to the main Iportion of the wall, or in other words, the ribs thus produced lie within the normal plane .of the outer face of the unribbed portions of such' body wall.

I have discovered that tunnel lining members of this type will have much greater strength if the reenforcing ribs are outset with respect to the body wall. This is due to the fact that the outer portions or face walls of said ribs are thus located at a greater distance from the neutral axis of the plate than are the unribbed portions of the body wall, consequently their moment of inertia about the neutral axis and the section modulus is greatly increased, whereas inset ribs being of course located closer to the neutral axis, do-not produce the same advantageous effect.

The object therefore of the present invention is to provide a novel structure of this type having greater strength than has heretofore been obtained, the structure being as readily produced and requiring no more metal in the formation.

A further and important objectv is to provide a anged structure of this kind in which the ange elements are themselves reenforced, thereby strengthening the member as a whole and further increasing lthe section modulus by providing additional metal remote from the neutral axis.

In the accompanying drawings:

Figure 1 is a side elevation of one embodiment of the invention.

Figure 2 is a bottom plan view of the same.

Figure 3 is a cross sectional view on the line 4@ 3-3 of Figure 1.

Figure 4 is a longitudinal sectional view on the line 4-4 of Figure 2.

Figure 5 is a bottomplan view of a. modified form of construction.

Figure 6 is a cross sectional view on the line 6-6 of Figure 5.

Referring rst to the embodiment disclosed in Figures 1-4 inclusive, a tunnel liner member or section is therein disclosed, which is constructed of plate metal, deformed to provide an oblong longitudinally curved body wall 7, provided along ,its side and end edges with right' angularly disposed anges 8. These flanges have tie bolt receiving openings 9 by which they are secured both at their sides'and ends to coasting members, as

ribs on the outer curved body wall thereof. Theseis well understood by those skilled in the art. The neutral axis of this member is indicated in Figure 3 by the line X-X, which neutral axis,

it will be noted, lies well within the inner face 6o of the body wall 7.

Upset or embossed on the body wall 7 are 1ongitudinally disposed reenforcing ribs l0 which it will be noted outstand from the outer face of said body wall. These ribs 10 preferably have transversely flat facing walls 11 connected at their edges with the body wall 7 by relatively sharp side walls 12. The ribs therefore are of considerable area as compared to the unribbed portions of said body wall 7.

As will be clear by reference to Figure 3, by reason of the formation the broad flat facing walls 11 of the ribs are set out a greater distance from the-neutral axis X-X than arethe unribbed portions 7 of the body wall and this has been found to result in a very material increase in the strength of the member over prior structures of which I am aware.

For example taking a formed plate 1A; inch in thickness, having a sectional area of 2.4047 square inches and anges 11/2 inches in height, with inset 'ribs corresponding in shape to those shown, the moment of inertia about the neutral axis, in inches4 is .213 and the section modulus, in inches3 is .184. With an exactly similar member formed according to the present invention, to-wit, with outstanding reenforcing ribs, the moment of inertia is found to be .386 as against said .213 and the section modulus .257 l as against said .184. This advantageous increase in strength is found in all other members of different sizes and different gages of metal. Ihus a member having a sectional area of 7.0779 square inches made of inch thickness and having anges 2 inches wide, with the inset reenforcing ribs the moment of inertia is 1.1746

as against 1.9516 in a corresponding structure with outstanding ribs as disclosed, while the section modulus of the former is .793 as against 1.086 of the latter.

The same structure as above described is illustrated in Figures 5`and 6, except that the side flanges are in turn reenforced. That is to say, the outer body wall here designated 7a is provided with longitudinal ribs 10a corresponding in all respects to those already described and the side flanges 8a likewise correspond with the flanges 8 of the first described embodiment, except that these flanges 8a have inset ribs 13 carried by their inner edges and formed by inturning the free margins of said side flanges.

From the foregoing, it is thought that Ithe construction, operation and many advantages of the herein described invention will be apparent to those skilled in the art without further description, and it will be understood that various changes in the size, shape, proportion and minor details of construction may be resorted to without departing from the spirit or sacriiicing any of the advantages of the invention.

What I claim, is:

1. A tunnel liner member of plate metal deformed to provide a curved outer Wall having longitudinal outstanding reinforcing ribs provided with face walls that are transversely at and having relatively sharp oiset side walls connecting the said face walls with the unribbed portions of the body Walls, said face Walls being located at a greater distance from the neutral axis of .the member than are the remaining portions of the body Wall.

2. A tunnel liner member of plate metal deformed to provide a curved outer body Wall having longitudinally disposed outset ribs above its outer face, the face walls of which are spaced a greater distance from the neutral axis of the member than are the remaining portions of the body wall, said body wall further having integral inset side flanges, said flanges having integral inset ribs along their inner edges.

3. A tunnel liner member of plate metal deformed to provide an outer curved face wall having longitudinally disposed spaced outset ribs provided with outer face walls that are transversely flat and relatively sharply offset side walls, the said face wall between the bases of ribs being transversely at and connecting the said offset side Walls.

v HERBERT E. WHITE. 

